The present invention relates to a cement admixture which comprises specific fluorine-containing compounds and concrete containing said cement admixture. The present invention further relates to a method for producing specific fluorine-containing compounds. The present invention still further relates to a novel surface active agent.
In order to improve the strength of the hardened product of concrete, it is most effective to reduce the water content of concrete. However, there are drawbacks that if the water content is reduced, fluidity of fresh concrete may decrease, whereby workability at the work site may significantly deteriorate.
In recent years, along with the increase in high-rise buildings, labor-saving is required, and fluidity of fresh concrete is thereby required. Simultaneously, the hardened product of concrete is required to have high strength including anti-earthquake property. Accordingly, concrete is required to satisfy both of the two performances which are in an antinomic relation to each other.
The following methods have been proposed for such requirements.
(1) A method to add, as an air-entraining agent (AE agent), a compound having terminal hydroxyl groups of (polyoxyethylene)aryl ether substituted by alkoxy groups to concrete to improve workability and freezing damage property, and to add an emulsion stabilizer for latex to prevent cracks.
(2) A method to use a block copolymer of oxyethylene and oxypropylene as a water reducing agent and a dispersing agent for concrete.
(3) A method to use an addition product of higher alcohol alkylene oxide, as an air-entraining agent and an emulsion stabilizer for latex.
(4) A method to use polyoxyalkylene glycol as a dispersing agent for e.g. asbestos or glass wool, which are fibers to be incorporated in concrete, and a method to use polyoxyalkylene glycol together with a cement dispersing agent such as lignin sulfonic acid, to further raise dispersibility of the fibers.
Further, the following methods have been proposed to reduce the shrink of the hardened product of concrete.
(5) A method to add an alkylene oxide compound to concrete (JP-A-2-1789).
(6) A method to add a compound having a higher carboxylic acid and alkylene oxide added thereto, to concrete (JP-A-5-70196, JP-A-3-290342).
Further, the following method has been proposed to obtain high hardness.
(7) A method to add a surface active agent containing an anionic surface active agent which comprises a hydrocarbon compound as a main component, to concrete.
Further, the following methods have been proposed to prevent reduction in fluidity of concrete when the water content is reduced.
(8) A method to add a surface active agent of fluorine type which comprises a compound having e.g. a sulfonyl bond, an ester bond or an amide bond, inserted between a perfluoroalkyl group and an oxyalkylene group (JP-A-7-17752).
(9) A method to use a surface active agent of hydrocarbon type together with the surface active agent of fluorine type as mentioned in (8) (JP-A-2-1789, JP-A-1-53215).
On the other hand, as the method for producing a compound containing a perfluoroalkyl group and an oxyalkylene group, the following methods have been proposed.
(10) A method in which a compound having a perfluoroalkyl group and a hydroxyl group connected therewith by means of an ethylene group (hereinafter referred to as perfluoroalkyl ethanol) is used as an initiator, and when ring opening polymerization of the alkylene oxide therewith is conducted, a three way catalyst made of NaI/I2/NaBH4 is used (WO95-35272).
(11) A method to react a tosylate of polyalkylene glycol with a perfluoroalkyl ethanol (JP-B-7-103059).
(12) A method in which perfluoroalkyl ethanol is used as an initiator, and when ring opening polymerization of the alkylene oxide compound therewith is conducted, a double metal cyanide complex is used as a catalyst (JP-A-3-290430).
However, there are following drawbacks in the above-mentioned proposals.
In the methods (1) to (4), both performances of strength after concrete is hardened and fluidity of fresh concrete are inadequate.
In proposals (5) and (6), in the case where the water content is reduced, a drawback is confirmed such that fluidity of fresh concrete decreases.
In the method (7), in order to obtain performance, it is required to add a large amount of surface active agent, and even if a large amount of surface active agent is added, strength and fluidity are inadequate.
In the methods (8) and (9), when the surface active agent is added to concrete, a problem of foaming phenomenon (a phenomenon such that foams are likely to foam, and formed foams hardly disappear) is confirmed. Further, concrete is likely to involve air during mixing, whereby apparent density after hardened decreases, and as a result, a problem such that the strength of the hardened product of concrete decreases is confirmed. Particularly in the case of employing a conventional fluorine-containing surface active agent having an amide bond or an ester bond between a perfluoroalkyl group and an oxyalkylene group, foaming phenomenon is significant, and depending upon the conditions of use of concrete, a problem such that the fluorine-containing surface active agent is hydrolyzed is confirmed. Further, among fluorine-containing surface active agents as described in the above references, some are hardly available practically, and some are extremely expensive even if they are available, whereby some of the fluorine-containing surface active agents can not be used practically.
Further, there are following problems in the above-mentioned method.
In the method (10), a special catalyst is used, and the control of the reaction is difficult. Further, it is disadvantageous in view of cost, and the method can not be industrially used practically. Further, the foaming phenomenon is confirmed.
In the method (11), the side reaction occurs, whereby the yield of the desired compound will be extremely low.
In the method (12), purification after the reaction takes a lot of time and labor. Further, in the case where the metal complex remains in the compound obtained by said method, performance as a cement admixture tends to decrease.
In each method (10) to (12), if it is attempted to change the structure of the initiator or to change the kind of the oxyalkylene group, the reaction is less likely to proceed, and such methods can not be used widely.
The present inventors have studied on a cement admixture, i.e. compounds having an excellent performance as an additive to be added to concrete for the purpose of improving fluidity, and found a mixture of the following fluorine-containing compounds. Further, they have found a method for effectively producing specific fluorine-containing compounds among said compounds, and a novel surface active agent.
Namely, the present invention provides a cement admixture which is a mixture of fluorine-containing compounds represented by the formula (1), and which is fluorine-containing compounds having a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (i.e. Mw/Mn) of at least 1.1:
Rfxe2x80x94Q1xe2x80x94Oxe2x80x94(A1xe2x80x94O)kxe2x80x94R1 xe2x80x83xe2x80x83(1) 
wherein Rf is a C1-22 polyfluoroaliphatic hydrocarbon group which may contain ethereal oxygen atoms or thioethereal sulfur atoms, Q1 is a C1-5 linear or branched alkylene group, k is an integer of from 1 to 100, A1 is a C2-4 linear alkylene group or a group having at least one hydrogen atom of said alkylene group substituted by a hydrocarbon group which may contain ethereal oxygen atoms, provided that when k is from 2 to 100, the plurality of A1 may be the same or different, and R1 is a hydrogen atom, a C1-18 hydrocarbon group or a C1-18 acyl group, concrete which contains the cement admixture, a method for producing fluorine-containing oxyalkylene compounds and a novel surface active agent.
The mixture having a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw/Mn) of at least 1.1 of the present invention, is a mixture of fluorine-containing compounds represented by the formula (1). Hereinafter xe2x80x9cthe fluorine-containing compound represented by the formula (1)xe2x80x9d is referred to as xe2x80x9cfluorine-containing compound (formula (1))xe2x80x9d, and xe2x80x9cthe mixture of the fluorine-containing compounds (formula (1)) having a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw/Mn) of at least 1.1xe2x80x9d is referred to as xe2x80x9cfluorine-containing compounds (mixture)xe2x80x9d.
xe2x80x9cThe hydrocarbon groupxe2x80x9d in the present specification basically means a hydrocarbon group comprising only carbon atoms and hydrogen atoms. Only when it is specified that ethereal oxygen atoms may be contained or thioethereal sulfur atoms may be contained, said hydrocarbon group may contain atoms besides carbons atoms and hydrogen atoms.
xe2x80x9cThe hydrocarbon groupxe2x80x9d refers to both xe2x80x9caliphatic hydrocarbon groupxe2x80x9d and xe2x80x9caromatic hydrocarbon groupxe2x80x9d. As the aliphatic hydrocarbon group, an alkyl group and an alkenyl group are preferred. Further, at least one hydrogen atom of the aliphatic hydrocarbon group may be substituted by an aromatic hydrocarbon group. A benzyl group may, for example, be mentioned.
Further, as the aromatic hydrocarbon group, a phenyl group is preferred.
Rf in the compound represented by the formula (1) of the present invention means a C1-22 polyfluoroaliphatic hydrocarbon group which may contain ethereal oxygen atoms or thioethereal sulfur atoms. xe2x80x9cThe polyfluoroaliphatic hydrocarbon group which may contain ethereal oxygen atoms or thioethereal sulfur atomsxe2x80x9d is hereinafter referred to as xe2x80x9cRf groupxe2x80x9d. The Rf group means a group having at least two hydrogen atoms in the aliphatic hydrocarbon group substituted by fluorine atoms.
Further, Rf group in the formula (1) is preferably a group having at least one fluorine atom bonded to the carbon atom adjacent to Q1.
The number of carbons in Rf group is from 1 to 22, preferably from 4 to 16, particularly preferably from 6 to 14. The higher the number of carbons in Rf group, the lower surface tension and the lower volatility, such being favorable. However, too high number of carbons is unfavorable in view of cost.
Rf group is preferably a polyfluoroalkyl group which may contain ethereal oxygen atoms or thioethereal sulfur atoms. Said polyfluoroalkyl group means a group having at least two hydrogen atoms of an alkyl group which may contain ethereal oxygen atoms or thioethereal sulfur atoms substituted by fluorine atoms. xe2x80x9cA polyfluoroalkyl group which may contain ethereal oxygen atoms or thioethereal sulfur atomsxe2x80x9d is hereinafter referred to as xe2x80x9cRF groupxe2x80x9d.
Among such RF groups, a polyfluoroalkyl group which does not contain ethereal oxygen atoms or thioethereal sulfur atoms, is preferred.
The number of carbons in RF group is preferably from 4 to 16, particularly preferably from 6 to 14.
Further, in the case where the number of fluorine atoms in RF group is represented by (number of fluorine atoms in RF group)/(number of hydrogen atoms in an alkyl group corresponding to RF group having the same number of carbons)xc3x97100 (%), it is preferably at least 60%, particularly preferably at least 80%. RF group is preferably linear or branched, and it is particularly preferably linear. In the case where it is branched, it is preferred that the branched part is a short chain having a number of carbons of from about 1 to about 3, and exists at the terminal part of RF group. Further, in the case where unsubstituted hydrogen atoms are contained in RF group, said hydrogen atoms may be substituted by chlorine atoms.
Rf group is preferably a perfluoroalkyl group having substantially all hydrogen atoms of the alkyl group which may contain ethereal oxygen atoms or thioethereal sulfur atoms substituted by fluorine atoms. Among such perfluoroalkyl groups, a perfluoroalkyl group which does not contain ethereal oxygen atoms or thioethereal sulfur atoms is preferred.
The perfluoroalkyl group is preferably linear. The number of carbons of the perfluoroalkyl group is preferably from 1 to 18, more preferably from 4 to 16, particularly preferably from 6 to 14. Namely, the perfluoroalkyl group is preferably a linear group represented by CF3(CF2)mxe2x80x94, wherein m is an integer of from 3 to 15.
As the specific example of the polyfluoroalkylene group, following examples are mentioned. In the following examples, groups corresponding to structural isomers of each group are included.
C4F9xe2x80x94 [structural isomers such as CF3(CF2)3xe2x80x94, (CF3)2CFCF2xe2x80x94, (CF3)3Cxe2x80x94 and CF3CF2CF(CF3)xe2x80x94], C5F11xe2x80x94 [structural isomers such as CF3(CF2)4xe2x80x94, (CF3)2CF(CF2)2xe2x80x94, (CF3)3CCF2xe2x80x94 and CF3(CF2)2CF(CF3)xe2x80x94], C8F17xe2x80x94, C10F21xe2x80x94, C12F25xe2x80x94, C14F29xe2x80x94, C16F33xe2x80x94, C18F37xe2x80x94, (CF3)2CFCsF2sxe2x80x94, wherein s is an integer of from 1 to 22, and HCtF2txe2x80x94, wherein t is an integer of from 1 to 22.
Further, as the specific example of the polyfluoroalkyl group which contains ethereal oxygen atoms or thioethereal sulfur atoms, the following examples may be mentioned. Here, u means an integer of from 1 to 6, v means an integer of from 1 to 6, w means an integer of from 1 to 10, and m means an integer of from 1 to 6.
CF3(CF2)4OCF(CF3)xe2x80x94, F[CF(CF3)CF2O]uCF(CF3)xe2x80x94, F(CF2CF2CF2O)vCF2CF2xe2x80x94, F(CF2CF2O)wCF2CF2xe2x80x94 and F[CF(CF3)CF2O]mCF(CF3)xe2x80x94.
CF3(CF2)4SCF(CF3)xe2x80x94, F[CF(CF3)CF2S]uCF(CF3)xe2x80x94, F(CF2CF2CF2S)vCF2CF2xe2x80x94, F(CF2CF2S)wCF2CF2xe2x80x94 and F[CF(CF3)CF2S]mCF(CF3)xe2x80x94.
Further, the fluorine-containing compounds (mixture) of the present invention may be a mixture of at least two compounds having different numbers of carbons in Rf group.
Q1 in the fluorine-containing compound (formula (1)) is a C1-5 linear or branched alkylene group. Namely, the fluorine-containing compound (formula (1)) is a compound having a linear connecting group such as a methylene group (xe2x80x94CH2xe2x80x94), a dimethylene group (xe2x80x94CH2CH2xe2x80x94), a trimethylene group (xe2x80x94CH2CH2CH2xe2x80x94), a tetramethylene group (xe2x80x94CH2CH2CH2CH2xe2x80x94) or a pentamethylene group (xe2x80x94CH2CH2CH2CH2CH2xe2x80x94), inserted between the above-mentioned Rf group and the oxyalkylene group, or a compound having a branched connecting group such as xe2x80x94CH2CH(CH3 )xe2x80x94 (propylene group), xe2x80x94CH2CH(CH3)CH2xe2x80x94, CH2CH2CH(CH3)xe2x80x94, xe2x80x94CH2CH2CH(CH3)CH2xe2x80x94 or xe2x80x94CH2CH2CH2CH(CH3)xe2x80x94, inserted therebetween.
The connecting group is a connecting group which prevent foaming and involving of air, and a connecting group which contributes to imparting chemical stability to the compound, in the case where the fluorine-containing compound is used as a cement admixture.
Q1 in the fluorine-containing compound (formula (1)) is preferably a C2-5 linear or branched alkylene group, more preferably a C3-4 linear or branched alkylene group. A compound having Q being a C3 linear or branched alkylene group, is a compound which is excellent in chemical stability as dispersed in water, and is excellent in heat resistance. A compound having Q being a C4 linear or branched alkylene group, is a compound which is excellent in chemical stability as dispersed in water, which is excellent in chemical stability also as dispersed in an alkaline aqueous solution, and which is excellent in heat resistance, and it is thereby most excellent compound to be used for a cement admixture.
k in the fluorine-containing compound (formula (1)) means an integer of from 1 to 100. It is preferably from 1 to 50, particularly preferably from 1 to 30. The fluorine-containing compounds (mixture) of the present invention are mixtures having at least two fluorine-containing compounds (formula (1)) having different values of k. When the average of k in the fluorine-containing compounds (mixture) is taken as kav, kav is preferably within a range of from 3 to 50, more preferably within a range of from 5 to 30, particularly preferably within a range of from 5 to 15.
The fluorine-containing compounds (mixture) are required to have a ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) (Mw/Mn) being at least 1.1. Compounds having Mw/Mn of less than 1.1 do not have adequate effect to suppress foamability. Mw/Mn is preferably at most 1.5, more preferably at most 1.3, most preferably at most 1.2.
As a factor to give the value of Mw/Mn being at least 1.1 to the fluorine-containing compounds (mixture), it may be mentioned that the molecular weight of each compound is different with each other, since any of Rf, Q1, A1, k and R1 in the formula (1) is different. In the present invention, preferred are fluorine-containing compounds (mixture) having Mw/Mn of at least 1.1 due to difference in the value of k, or the value of k and Rf, among compounds.
Particularly fluorine-containing compounds (mixture) having Mw/Mn of at last 1.1, due to broad distribution of the values of k of each compound in the mixture, are preferred. When the average value of k of said mixture is kav, it is preferred that k of each compound in the mixture distributes to a wide range of from 0 to about 3 kav. Although the mechanism is not clear, it is considered that the broadness of the distribution has some influences on suppression of foaming.
A1 in the fluorine-containing compound (formula (1)) is a C2-4 linear alkylene group or a group having at least one hydrogen atom of said alkylene group substituted by a hydrocarbon group which may contain ethereal oxygen atoms.
As the C2-4 linear alkylene group, a dimethylene group, a trimethylene group or a tetramethylene group may be mentioned.
Further, A1 may be a group having at least one hydrogen atom of the above-mentioned alkylene group substituted by a hydrocarbon group which may contain ethereal oxygen atoms.
As the hydrocarbon group which may contain ethereal oxygen atoms, a group such as an alkyl group, a phenyl group or a benzyl group, or a group having ethereal oxygen atoms inserted between the carbon-carbon linkage or at the terminals of such a group, may be mentioned.
As specific examples of A1, the following examples may be mentioned. Ph means a phenyl group.
xe2x80x94CH2CH(CH3)xe2x80x94(propylene group), xe2x80x94CH2CH(CH2CH3)xe2x80x94, xe2x80x94CH(CH3)CH(CH3)xe2x80x94, xe2x80x94C(CH3)2CH2xe2x80x94, xe2x80x94CH2CH2CH (CH3)xe2x80x94, xe2x80x94CH2CH(CH3)CH2xe2x80x94, xe2x80x94CH2CH[CH2OCH2CH(CH2CH3)(CH2)3CH3]xe2x80x94, xe2x80x94CH2CH(CH2OPh)xe2x80x94 and xe2x80x94CH2CH(OPh)xe2x80x94.
Among these, A1 of the fluorine-containing compound (formula (1)) is preferably xe2x80x94CH2CH2xe2x80x94, xe2x80x94CH2CH(CH3)xe2x80x94, xe2x80x94CH2CH(CH2CH3)xe2x80x94 or xe2x80x94CH2CH2CH2CH2xe2x80x94.
Further, in the case where k is an integer of from 2 to 100, the plurality of A1 in the fluorine-containing compound (formula (1)) may be the same or different. In the case where they are different, the number of kinds of A1 is preferably 2 or 3, particularly preferably 2. The number of kinds of A1 in the fluorine-containing compound (formula (1)) is preferably 1 or 2, and only one kind of ethylene groups or two kinds of ethylene groups and propylene groups, are particularly preferred.
The fluorine-containing compounds (mixture) of the present invention are preferably one having characteristic such that they can be dissolved or dispersed in water. Accordingly, it is preferred that an oxyethylene group which is a hydrophilic group is essential as the oxyalkylene group. Namely, it is preferred that the fluorine-containing compounds (mixture) contains the fluorine-containing compound (formula (1)) containing an oxyethylene group as (A1xe2x80x94O) in the fluorine-containing compound (formula (1)).
In such a case, preferably at least 20%, particularly preferably at least 50%, more preferably at least 70%, by number, of the total oxyalkylene groups in the fluorine-containing compounds (mixture) are oxyethylene groups.
R1 in the fluorine-containing compound (formula (1)) means a hydrogen atom, a C1-18 hydrocarbon group or a C1-18 acyl group.
In the case where R1 is a C1-18 hydrocarbon group, a C1-5 hydrocarbon group is preferred, and a C1-5 alkyl group is more preferred. CH3xe2x80x94, C2H5xe2x80x94, linear or branched C3H7xe2x80x94, linear or branched C4H9 xe2x80x94, or linear or branched C5H11xe2x80x94, may be mentioned.
In the case where R1 is a C1-18 acyl group, as said acyl group, a C1-10 acyl group is preferred, and a C1-6 acyl group is particularly preferred. When R1 is an acyl group, the fluorine-containing compound (formula (1)) has a structure containing an ester linkage at the terminal of the molecule, whereby the foamability is suppressed.
Further, when said acyl group is represented by R10COxe2x80x94, the R10 part is preferably a C1-17 alkyl group or alkenyl group.
As specific examples of the acyl group (R10COxe2x80x94), a group such as CH3COxe2x80x94, CH3CH2COxe2x80x94, CH3(CH2)2COxe2x80x94, CH3(CH2)3CH(CH2CH3)COxe2x80x94, CH3(CH2)7CHxe2x95x90CH(CH2)7COxe2x80x94 or CH3(CH2)16COxe2x80x94, may, for example, be mentioned.
Among these, a hydrogen atom or a methyl group is preferred as R1, and hydrogen atom is particularly preferred.
As the fluorine-containing compound (formula (1)) of the present invention, a compound represented by the formula (1A) or the following formula (1B) is preferred. Here, the linkage of oxyethylene groups and oxypropylene groups in the formula (1B) may be block or random. In the case of the block chain, it is preferred that the polyoxypropylene group links to Rf(CH2)3Oxe2x80x94, and the polyoxyethylene group links to said polyoxypropylene group.
Here, Rf and R1 in the formulae (1A) and (1B) are as defined for the formula (1), and the preferred modes are also as defined for the formula (1).
In the formula (1A), a is an integer of from 1 to 100, preferably from 1 to 50, particularly preferably from 3 to 30.
In the formula (1B), b is an integer of from 1 to 100, c is an integer of from 0 to 100, and 1xe2x89xa6b+cxe2x89xa6100. Further, b is preferably an integer of from 1 to 30, c is preferably an integer of from 0 to 20, and preferably 1xe2x89xa6b+cxe2x89xa630. Further, preferably 0.2xe2x89xa6b/(b+c)xe2x89xa61, more preferably 0.5xe2x89xa6b/(b+c)xe2x89xa61, and particularly preferably 0.7xe2x89xa6b/(b+c)xe2x89xa61:
Rf(CH2)3O(CH2CH2O)aR1 xe2x80x83xe2x80x83(1A) 
Rf(CH2)3Oxe2x80x94[CH(CH3)CH2O]c(CH2CH2O)bR1 xe2x80x83xe2x80x83(1B) 
Specific examples of the fluorine-containing compound (formula (1)) include the following compounds. However, it is not restricted thereto. In the following formulae, the moiety corresponding to the perfluoroalkyl group may be linear or branched, and it is preferably linear. When at least two oxyalkylene moieties exist, the linkage may be block or random. The (C3H6O) moiety means an oxypropylene group, and is [CH(CH3)CH2O] or [CH2CH(CH3)O]:
C6F13(CH2)3O(CH2CH2O)5H,
C6F13(CH2)3O(CH2CH2O)8H,
C7F15(CH2)3O(CH2CH2O)5H,
C8F17(CH2)3O(CH2CH2O)5H,
C8F17(CH2)3O(CH2CH2O)10H,
C6F13(CH2)3O(C3H6O)5(CH2CH2O)10H,
C7F15(CH2)3O(C3H6O)5(CH2CH2O)10H,
C8F17(CH2)3O(C3H6O)5(CH2CH2O)10H,
C6F13(CH2)3O(C3H6O)4(CH2CH2O)15H,
C7F15(CH2)3O(C3H6O)4(CH2CH2O)15H,
C8F17(CH2)3O(C3H6O)4(CH2CH2O)15H,
C6F13(CH2)3O(CH2CH2CH2CH2O)5H,
C6F13(CH2)3O(CH2CH2CH2CH2O)8H,
C7F15(CH2)3O(CH2CH2CH2CH2O)5H,
C8F17(CH2)3O(CH2CH2CH2CH2O)5H,
C8F17(CH2)3O(CH2CH2CH2CH2O)10H,
C8F17(CH2)3O(CH2CH2CH2CH2O)20H,
C6F13(CH2)3O(CH2CH2O)5CH3,
C6F13(CH2)3O(CH2CH2O)8C2H5,
C7F15(CH2)3O(CH2CH2O)5COCH3,
C8F17(CH2)3O(CH2CH2O)5COCH3,
C8F17(CH2)3O(CH2CH2O)10COCH3,
C6F13(CH2)4O(CH2CH2O)5H,
C6F13(CH2)4O(CH2CH2O)8H,
C7F15(CH2)4O(CH2CH2O)5H,
C8F17(CH2)4O(CH2CH2O)5H,
C8F17(CH2)4O(CH2CH2O)10H,
C6F13(CH2)4O(C3H6O)5(CH2CH2O)10H,
C7F15(CH2)4O(C3H6O)5(CH2CH2O)10H,
C8F17(CH2)4O(C3H6O)5(CH2CH2O)10H,
C6F13(CH2)4O(C3H6O)4(CH2CH2O)15H,
C7F15(CH2)4O(C3H6O)4(CH2CH2O)15H,
C8F17(CH2)4O(C3H6O)4(CH2CH2O)15H,
C6F13(CH2)4O(CH2CH2CH2CH2O)5H,
C6F13(CH2)4O(CH2CH2CH2CH2O)8H,
C7F15(CH2)4O(CH2CH2CH2CH2O)5H,
C8F17(CH2)4O(CH2CH2CH2CH2O)5H,
C8F17(CH2)4O(CH2CH2CH2CH2O)10H,
C8F17(CH2)4O(CH2CH2CH2CH2O)20H,
C6F13(CH2)4O(CH2CH2O)5CH3,
C6F13(CH2)4O(CH2CH2O)8C2H5,
C7F15(CH2)4O(CH2CH2O)5COCH3,
C8F17(CH2)4O(CH2CH2O)5COCH3,
C8F17(CH2)4O(CH2CH2O)10COCH3,
C6F13(CH2)5O(CH2CH2O)5H,
C6F13(CH2)5O(CH2CH2O)8H,
C7F15(CH2)5O(CH2CH2O)5H,
C8F17(CH2)5O(CH2CH2O)5H,
C8F17(CH2)5O(CH2CH2O)10H,
C6F13(CH2)5O(C3H6O)5(CH2CH2O)10H,
C7F15(CH2)5O(C3H6O)5(CH2CH2O)10H,
C8F17(CH2)5O(C3H6O)5(CH2CH2O)10H,
C6F13(CH2)5O(C3H6O)4(CH2CH2O)15H,
C7F15(CH2)5O(C3H6O)4(CH2CH2O)15H,
C8F17(CH2)5O(C3H6O)4(CH2CH2O)15H,
C6F13(CH2)5O(CH2CH2CH2CH2O)5H,
C6F13(CH2)5O(CH2CH2CH2CH2O)8H,
C7F15(CH2)5O(CH2CH2CH2CH2O)5H,
C8F17(CH2)5O(CH2CH2CH2CH2O)5H,
C8F17(CH2)5O(CH2CH2CH2CH2O)10H,
C8F17(CH2)5O(CH2CH2CH2CH2O)20H,
C6F13(CH2)5O(CH2CH2O)5CH3,
C6F13(CH2)5O(CH2CH2O)8C2H5,
C7F15(CH2)5O(CH2CH2O)5COCH3,
C8F17(CH2)5O(CH2CH2O)5COCH3,
C8F17(CH2)5O(CH2CH2O)10COCH3,
C6F13(CH2)2CH(CH3)O(CH2CH2O)5H,
C6F13(CH2)2CH(CH3)O(CH2CH2O)8H,
C7F15(CH2)2CH(CH3)O(CH2CH2O)5H,
C8F17(CH2)2CH(CH3)O(CH2CH2O)5H,
C8F17(CH2)2CH(CH3)O(CH2CH2O)10H,
C6F13(CH2)2CH(CH3)O(C3H6O)5(CH2CH2O)10H,
C7F15(CH2)2CH(CH3)O(C3H6O)5(CH2CH2O)10H,
C8F17(CH2)2CH(CH3)O(C3H6O)5(CH2CH2O)10H,
C6F13(CH2)2CH(CH3)O(C3H6O)4(CH2CH2O)15H,
C7F15(CH2)2CH(CH3)O(C3H6O)4(CH2CH2O)15H,
C8F17(CH2)2CH(CH3)O(C3H6O)4(CH2CH2O)15H,
C6F13(CH2)2CH(CH3)O(CH2CH2CH2CH2O)5H,
C6F13(CH2)2CH(CH3)O(CH2CH2CH2CH2O)8H,
C7F15(CH2)2CH(CH3)O(CH2CH2CH2CH2O)5H,
C8F17(CH2)2CH(CH3)O(CH2CH2CH2CH2O)5H,
C8F17(CH2)2CH(CH3)O(CH2CH2CH2CH2O)10H,
C8F17(CH2)2CH(CH3)O(CH2CH2CH2CH2O)20H ,
C6F13(CH2)2CH(CH3)O(CH2CH2O)5CH3,
C6F13(CH2)2CH(CH3)O(CH2CH2O)8C2H5,
C7F15(CH2)2CH(CH3)O(CH2CH2O)5COCH3,
C8F17(CH2)2CH(CH3)O(CH2CH2O)5COCH3 and
C8F17(CH2)2CH(CH3)O(CH2CH2O)10COCH3.
Some of the fluorine-containing compounds (formula (1)) of the present invention may be produced by the above-mentioned known methods. However, the known production methods have drawbacks as mentioned above. Accordingly, for effective production, it is preferred to synthesize the fluorine-containing compound (formula (1)) by the following method.
The method mentioned hereinafter is a method suitably applied to the fluorine-containing compound (formula (1)) wherein Q1 is a C3-5 linear or branched alkylene group. In view of easiness to obtain materials, the method is particularly preferred for compounds of C3-4 linear or branched alkylene group. Further, it is a particularly preferred method as a method for producing the fluorine-containing compounds for the cement admixture of the present invention.
The present invention also provides the following method for producing fluorine-containing compounds.
Namely, it is a method to obtain fluorine-containing oxyalkylene compounds represented by the formula (4), which comprises ring opening polymerization of at least one cyclic ether represented by the formula (3) in the presence of an acid catalyst and a fluorine-containing hydroxyl compound represented by the formula (2):
Rfxe2x80x94Q2xe2x80x94OH xe2x80x83xe2x80x83(2) 

Rfxe2x80x94Q2xe2x80x94Oxe2x80x94(A2xe2x80x94O)kxe2x80x94H xe2x80x83xe2x80x83(4) 
wherein Rf is a C1-22 polyfluoroaliphatic hydrocarbon group which may contain ethereal oxygen atoms or thioethereal sulfur atoms, Q2 is a C3-5 linear or branched alkylene group, k is an integer of from 1 to 100, and A2 is a C2-4 linear alkylene group or a group having at least one hydrogen atom of said alkylene group substituted by a hydrocarbon group which may contain ethereal oxygen atoms.
Further, the fluorine-containing oxyalkylene compound (formula (4)) can be induced to the formula (5), as the case requires, by converting the terminal hydroxyl group to a R3Oxe2x80x94 group, wherein R3 is a C1-18 hydrocarbon group or a C1-18 acyl group:
Rfxe2x80x94Q2xe2x80x94Oxe2x80x94(A2xe2x80x94O)kxe2x80x94R3 xe2x80x83xe2x80x83(5) 
wherein Rf, Q2 and k are as defined for the formula (4), and R3 is as defined above.
The compound represented by the formula (4) corresponds to a compound of the formula (1) wherein R1 is a hydrogen atom, and Q1 is a C3-5 linear or branched alkylene group. The compound represented by the formula (5) corresponds to a compound of the formula (1) wherein R1 is a C1-18 hydrocarbon group or a C1-18 acyl group, and Q1 is a C3-5 linear or branched alkylene group.
The fluorine-containing hydroxyl compound (formula (2)) is a known compound, and can be produced by known methods. It can be synthesized, for example, by adding allylalcohol to a perfluoroalkyl iodide, followed by substitution of the iodide atoms by hydrogen atoms by a reducing agent.
Further, the cyclic ether (formula (3)) which undergoes the ring opening polymerization in the presence of the fluorine-containing hydroxyl compound (formula (2)) has, as the A2 part, a C2-4 linear alkylene group or a group having at least one hydrogen atom of said alkylene group substituted by a hydrocarbon group which may contain ethereal oxygen atoms. Preferred modes of A2 are as defined for A1 in the formula (1).
The cyclic ether (formula (3)) may, for example, be ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, isobutylene oxide, oxetane, methyloxetane, phenyl glycidyl ether, tetrahydrofuran, styrene oxide or an alkyl glycidyl ether. The alkyl glycidyl ether may, for example, be methyl glycidyl ether, butyl glycidyl ether or 2-ethylhexyl glycidyl ether.
Among these, as the cyclic ether (formula (3)), ethylene oxide, propylene oxide, 1,2-butylene oxide and tetrahydrofuran are preferred.
At least one kind of the cyclic ether (formula (3)) may be used, and it is preferred to use one or two kinds of them.
In the case where at least two kinds of the cyclic ethers (formula (3)) undergo the ring opening polymerization, they may be mixed to conduct the reaction, or they may be successively reacted. Further, in either case of using one kind of the cyclic ether (formula (3)), or in the case of using at least two kinds of them, they may be charged at a stretch, or may be gradually added to the reaction system.
The amount of the cyclic ether (formula (3)) to the fluorine-containing hydroxyl compound (formula (2)) may be suitably changed depending upon the value of the k of the desired compound (in the case where a mixture is obtained, average k, i.e. kav). Usually, it is preferred to use it from 1 to 1.5 molar times the theoretical amount for the reaction.
The ring opening polymerization of the cyclic ether (formula (3)) in the presence of the fluorine-containing hydroxyl compound (formula (2)), is conducted in the presence of an acid catalyst.
As the acid catalyst, boron trifluoride, an ether complex of boron trifluoride, aluminum chloride, antimony pentachloride, ferric chloride or a condensed inorganic acid is preferred, and an ether complex of boron trifluoride is particularly preferred. As the condensed inorganic acid, a heteropoly-acid constituted by at least two metallic elements is preferred, and e.g. phosphomolybdic acid, phosphowolframate, silicomolybdic acid or silicotungstic acid is preferred.
The amount of the acid catalyst is preferably from 0.01 to 5 parts by weight, particularly preferably from 0.1 to 3 parts by weight, based on 100 parts by weight of the theoretical amount of the fluorine-containing oxyalkylene compound (formula (4)) produced.
The method of the present invention has an advantage that the reaction proceeds with a particularly high yield, when producing a compound of the formula (1) wherein Q1 is a C3-5 linear or branched alkylene group. Namely, with regard to a compound having a linear or branched alkylene group of a carbon number of at least 3 inserted between the Rf group and the hydroxyl group, such as the compound of the formula (2), since the electric absorptivity derived from the Rf group can be made adequately low, the reactivity of the terminal hydroxyl group will be high under the acid catalyst conditions, whereby side reactions such as production of an olefin due to separation of hydrogen are less likely to take place, such being advantageous.
Further, as the catalyst can be removed only by conducting a usual purification treatment after the reaction, it is not necessary to worry about bad influences derived from the catalyst, such being advantageous. Further, the kind of the alkylene oxide unit can be freely changed, the method of the present invention is thereby an excellent method to be used widely.
Usually, a compound obtainable by a method wherein a cyclic ether undergoes ring opening polymerization, is in many cases a mixture of compounds having different molecular weights. By the above-mentioned method of the present invention, fluorine-containing alkylene compounds represented by the formula (4) can be obtained, as a mixture of compounds having different molecular weights.
Namely, the present invention resides in a method for producing a mixture of the fluorine-containing oxyalkylene compounds represented by the formula (4), which comprises ring opening polymerization of at least one cyclic ether represented by the formula (3) in the presence of an acid catalyst and the fluorine-containing hydroxyl compound represented by the formula (2), said mixture having a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (i.e. Mw/Mn) of at least 1.1.
By the method of the present invention, particularly a mixture of fluorine-containing alkylene compounds (formula (4)) having Mw/Mn of at least 1.1 can be easily obtained. When a single compound is selected as the fluorine-containing hydroxyl compound (formula (2)), a mixture of the fluorine-containing alkylene compounds (formula (4)) having Mw/Mn of at least 1.1 can be obtained by the method. Accordingly, it is evident that the mixture of the fluorine-containing alkylene compounds (formula (4)) having different values of k, can be produced by the method.
To obtain a mixture of the fluorine-containing alkylene compounds (formula (4)) having Mw/Mn of at least 1.1 by the method, it is preferred to conduct the reaction by using a three-membered cyclic ether (formula (3)) wherein A2 is a C2 linear alkylene group or a group having at least one hydrogen atom of said alkylene group substituted by a hydrocarbon group which may contain ethereal oxygen atoms, as the essential component.
Further, in such a case, the distribution of the values of k of each compound in the mixture is considered to be broad. When the average value of k in the mixture is taken as kav, values of k of each compound distribute in a range of from 0 to 3 kav.
Further, it is particularly preferred to conduct the above-mentioned ring opening polymerization in the presence of a solvent, as a side reaction of separation of hydrogen atoms in the xe2x80x94CH2xe2x80x94 group bonded to the terminal of the Rf group, is prevented.
As the solvent, an ether solvent having no active hydrogen is preferred, and glyme (ethylene glycol dimethyl ether), diglyme (diethylene glycol dimethyl ether), triglyme (triethylene glycol dimethyl ether) or methyl tert-butyl ether is particularly preferred. The solvent may be used alone or as a mixture of at least two of them.
In the reaction wherein the cyclic ether (formula (3)) undergoes the ring opening polymerization in the presence of the fluorine-containing hydroxyl compound (formula (2)), the reaction temperature is preferably from xe2x88x9220xc2x0 C. to +180xc2x0 C., particularly preferably from 0xc2x0 C. to +130xc2x0 C. However, in the case where a solvent having a low boiling point is present in the reaction system, it is preferred to conduct reaction at a temperature lower than (the boiling point of the solvent +20)xc2x0 C., considering the increase in the internal pressure.
The amount of the fluorine-containing hydroxyl compound (formula (2)) charged into a reactor may be suitably changed depending upon the amount of the cyclic ether (formula (3)). In the case where effective stirring is attempted, it is preferred to charge it in an amount of at least one-tenth of the capacity of the reactor. Considering the volumetric efficiency, the amount of the product after the ring opening polymerization of the cyclic ether (formula (3)) is preferably from 80 to 95% in volume fraction.
In the reaction wherein the fluorine-containing hydroxyl compound (formula (3)) undergoes the ring opening polymerization in the presence of the cyclic ether (formula (2)), the fluorine-containing oxyalkylene compounds (formula (4)) are produced.
The fluorine-containing oxyalkylene compounds (formula (4)) can be induced to a compounds represented by the formula (5), by converting the terminal hydroxyl group to a R3Oxe2x80x94 group, wherein R3 is as defined above, as the case requires.
By converting the terminal hydroxyl group of the fluorine-containing oxyalkylene compounds (formula (4)) to an alkoxy group or an acyloxy group, various properties can be controlled.
As a method to convert the terminal hydroxyl group of the fluorine-containing oxyalkylene compound (formula (4)) to the xe2x80x94OR3 group, wherein R3 is a C1-18 hydrocarbon group, a known method for alkoxylation can be employed. It may, for example, be a method to react the fluorine-containing oxyalkylene compounds (formula(4)) with a C1-18 hydrocarbon monohalide under strong alkali condition, a method to react the fluorine-containing hydroxyalkylene compounds (formula(4)) with a C1-18 alkyl sulfuric acid, or a method to convert the hydroxyl group of the fluorine-containing hydroxyalkylene compounds (formula(4)) to a tosyloxy group, which then undergoes C1-18 alkoxylation.
Among these, the method to react the fluorine-containing hydroxyalkylene compounds (formula(4)) with an alkyl sulfuric acid, or the method to conduct alkoxylation of the tosyloxy group, is preferred, to suppress the reaction of fluorine-separation from the fluorine-containing oxyalkylene compound (formula (4)).
The method for converting the terminal hydroxyl group of the fluorine-containing oxyalkylene compounds (formula(4)) to C1-18 acyloxy group (hereinafter referred to as esterification), may be a method to react the fluorine-containing oxyalkylene compounds (formula(4)) with a monocarboxylic acid, or with an ester of monocarboxylic acid and an alcohol having a low boiling point (hereinafter such compounds are referred to as esterification agents).
The monocarboxylic acid may, for example, be acetic acid, propionic acid, butanoic acid, 2-ethyl hexanoic acid, n-octanoic acid, 3,5,5-trimethyl hexanoic acid (isononanoic acid), oleic acid or stearic acid.
As the ester of the above-mentioned monocarboxylic acid and an alcohol having a low boiling point, e.g. methyl acetate, ethyl acetate, butyl acetate, isopropyl acetate and methyl propionate are preferred.
The esterification can be conducted in such a manner that an esterification agent is added to the fluorine-containing hydroxyalkylene compounds (formula(4)), the mixture is heated and stirred for the reaction, and dehydration or dealcohol is conducted, or unreacted acids are distilled off.
The esterification can be conducted with or without a catalyst. In the case where a catalyst is present, preferred is a method wherein a trace amount of an acid catalyst such as p-toluene sulfonic acid or sulfuric acid is present, or a method wherein an alkali catalyst such as potassium hydroxide or sodium hydroxide is present.
A crude product obtained by the reaction to convert the terminal hydroxyl group of the fluorine-containing oxyalkylene compounds (formula (4)), is preferably purified by e.g. an acid treatment using sulfuric acid, phosphoric acid or the like, or an adsorption treatment using a synthetic magnesium, activated clay, activated carbon or the like, as the case requires.
In the present invention, the above-mentioned fluorine-containing compounds (mixture) are also used as a cement admixture. By incorporating said cement admixture in concrete, excellent fluidity can be imparted to concrete. This is considered to be attributable to the fact that the fluorine-containing compounds (mixture) have a chemical or physical action on cement particles in concrete, whereby secondary agglomeration of cement particles is prevented.
On the other hand, the fluorine-containing compounds (mixture) have a low foamability, and have an effect to easily eliminate foams once formed. Accordingly, concrete is less likely to involve air during mixing, whereby the strength of the hardened product of concrete will not be lowered, such being advantageous.
As the concrete, cement mortar obtained by blending sand into various cements, followed by kneading with water, or fresh concrete obtained by blending e.g. sand, shingle or water in a suitable ratio in said various cements, may be mentioned. As said cement, plain Portland cement, high-early-strength Portland cement, low heat Portland cement or Portland blast furnace cement may, for example, be mentioned.
As the time to incorporate the fluorine-containing compounds (mixture) in concrete, just like a conventional cement admixture, it may be added to cement when water, or various aggregates such as sand or shingle, as the case requires, are added to cement followed by mixing; the fluorine-containing compounds may be preliminarily dispersed or dissolved in water; or it may be added together with a surface active agent such as an air-entraining agent or a water reducing agent, or a dispersing agent.
The amount of the fluorine-containing compounds (mixture) may be less than 10 parts by weight based on 100 parts by weight of total concrete, and it may be from 300 to 1000 ppm.
The fluorine-containing compounds of the present invention have an advantage that excellent effects can be obtained with a significantly small amount of them, as compared with the amount of conventional cement admixture added (from 1 to 3 wt %).
The fluorine-containing compounds (mixture) of the present invention have effects that when they are dispersed in water, even when the dispersant is shook strongly, the foamability is low, and the foams once formed disappear quickly. Accordingly, they may be used for a use of e.g. an aqueous cleaner for which chlorinated fluorinated hydrocarbons are conventionally used, which requires a low foamability, or for a resin additive for the purpose of improving the resin, in addition for a use as a cement admixture.
The present invention further provides a novel surface active agent, i.e. a surface active agent which comprises fluorine-containing compounds represented by the formula (6):
Rfxe2x80x94CH2CH2CH(CH3)xe2x80x94Oxe2x80x94(A1xe2x80x94O)kxe2x80x94R1 xe2x80x83xe2x80x83(6) 
wherein Rf is a C1-22 polyfluoroaliphatic hydrocarbon group which may contain ethereal oxygen atoms or thioethereal sulfur atoms, k is an integer of from 1 to 100, A1 is a C2-4 linear alkylene group or a group having at least one hydrogen atom of said alkylene group substituted by a hydrocarbon group which may contain ethereal oxygen atoms, provided that when k is from 2 to 100, plurality of A1 may be the same or different, and R1 is a hydrogen atom, a C1-18 hydrocarbon group or a C1-18 acyl group.
The fluorine-containing compound represented by the formula (6) is a compound having a low surface tension. Said surface active agent may be used alone, or in combination as a mixture with other surface active agent.
The mixture of the fluorine-containing compounds represented by the formula (6), having a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (i.e. Mw/Mn) of at least 1.1, has effects that the foamability is low, and the foams once formed are easily eliminated, whereby it is more excellent as a surface active agent.
The cement admixture of the present invention comprises excellent compounds which impart excellent fluidity to fresh concrete. With regard to concrete in which said cement admixture is incorporated, workability is excellent, and the content of air can be suppressed, whereby a hardened product of concrete having suppressed foamability and high strength, can be obtained.
Further, by the method of the present invention, fluorine-containing compounds useful as a cement admixture can be effectively produced with a high yield.
The fluorine-containing compounds of the present invention have a low surface tension and a low foamability, whereby it may be used for an aqueous cleaner or for a resin additive for the purpose of improving the resin.
The present invention further provides a novel surface active agent.